Concern is mounting that commonly used pesticides are detrimental to children. Children are rapidly undergoing cognitive, sensory, and motor development, and disruption of normal maturation can have life-long consequences. The extant literature strongly indicates that prenatal exposure to pesticides leads to abnormal neurobehavioral development. A recent brain imaging study further showed that prenatal pesticide exposure is associated with disrupted anatomical brain development. However, results concerning the consequences of postnatal pesticide exposure are much less conclusive. Some studies have reported neurobehavioral deficits following postnatal pesticide exposure, but just as many studies have reported no negative consequences. Currently there are no studies that assess the effects of postnatal pesticide exposure on brain development using anatomical or functional brain imaging. More conclusive research on the effects of postnatal exposure on neurodevelopment requires a highly exposed population, a longitudinal design, and careful quantification of exposure and outcomes. We propose a two-group, prospective, longitudinal study of Latino children 7 years of age with quarterly measurement of cumulative pesticide exposure using passive dosimetry wristbands as well as documentation of prenatal and early life exposure through life history techniques. Children from Latino seasonal farmworker families will be compared with children from Latino families not participating in farm work and not living in an agricultural environment. Children in Latino farmworker families are at particularly high risk of exposure. Not only are pesticides frequently used in their low quality housing, but they are also exposed to agricultural pesticides used in nearby fields brought home by parental/sibling farmworkers on clothing. Children will be followed for 2 years with measurement of neurobehavioral function at baseline, 1 year, and 2 years. Neuroimaging will be performed in a subset of participants with structural and functional brain organization assessed at baseline and two years later. Specific aims for this project are: Aim 1: Compare 2-year longitudinal and prenatal/early life pesticide exposure between children of Latino seasonal farmworkers and children of Latino parents who are not farmworkers. Aim 2: Compare 2-year longitudinal neurobehavioral and emotional and behavioral functioning among children of Latino seasonal farmworkers relative to children of Latino parents who are not farmworkers. Aim 3: Compare 2-year longitudinal anatomical and functional brain development between children of Latino seasonal farmworkers and children of Latino parents who are not farmworkers. Our nearly two decades of environmental justice (EJ) and community-based participatory research (CBPR) on pesticide exposure with farmworkers and their families provides an auspicious context to engage this vulnerable population in a study of both scientific and environmental justice importance.